Maybe you notice a widening part or found a few extra strands in your baseball cap, but however you first notice your hair is thinning, it’s always a painful moment. It’s not just you: By the age 35, two-thirds of American men will experience some degree of hair loss, according to the American Hair Loss Association, and by the age 50 about 85% of men have significantly thinning hair. It starts earlier than you would guess: About 25% of men who suffer from it start losing their hair before they turn 21. While you can’t control your genes, you can control your lifestyle. Glynis Ablon, MD, FAAD, Associate Clinical Professor at UCLA, and Dove Men+Care consulting dermatologist, shares 10 reasons you’re losing you hair—and how save your strands.

Heredity

Genes have a major impact on thinning hair, and there’s research to prove it, including a study published in 2015 the journal PLoS One. “Hair loss is a result of a complicated set of both environmental and genetic factors, and how these factors play out are specific to each individual,” says Dr. Ablon. “It’s rare, but some men can start losing their hair as early as 18, while others have a full head of hair when they’re 90.” However, it’s important to understand the difference between hair loss and hair fall due to breakage. “When we talk about hair fall specifically, this isn’t something that is just impacted by genetics—everyday things your hair goes through like aggressive towel drying and even UV exposure can impact overall hair health,” says Dr. Ablon.

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UV rays

Fun in the sun can take a toll on your locks and cause hair to thin. “Strong UV rays can degrade the bonds that hold hair together, causing brittleness, dryness, breakage and lack of manageability,” Dr. Ablon says. “You might not always be able to feel the burn, but the sun’s rays can cause hair fall or shedding.” Guys shouldn’t feel like they can’t enjoy a day outside—just be mindful of the best ways to protect against it, such as hair SPFs, wearing a hat, and restoring moisture to the hair with a conditioning shampoo.

Aggressive towel drying

When you get out of the shower, if you’re like most guys, you probably vigorously dry your hair with a towel without giving it much thought. However, it’s actually quite destructive to your hair’s cuticles, or the outer layer of each strand. “Your hair’s structure is held together by three kinds of bonds, which contribute to the strength of your hair,” Dr. Ablon explains. “When the hair is wet, it swells and the cuticle lifts up a little. When it dries, it comes back to its original position. When the cuticle is slightly lifted during the wet stage, it’s vulnerable to things that come in contact with it, such as your towel vigorously rubbing up against it.” Luckily, there are simple things you can do to minimize damage. First, use a hair conditioner or a conditioning shampoo that coats each strand of hair so that your cuticles are protected. Second, change the way you dry your hair. Instead of rubbing your wet head with a towel, pat the hair dry.

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Chlorine

Taking a dip in the pool is fun—but not for your hairline. “Chlorine damages the hair by removing natural oils from hair’s strands and weakens the chemical bonds between hair fibers, leaving them prone to dryness, breakage and ultimately hair fall,” explains Dr. Ablon. “Enlist a moisturizing shampoo and conditioner daily, such as the Dove Men+Care Complete Care Fortifying Shampoo + Conditioner ($3.49, drugstores). Not only will this help promote hair’s health to stand up to the effects of chlorine, but it will also help restore moisture and strengthen hair after it has been exposed.”

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Wearing a hat

We get the irony here—wearing a hat is an easy way to hide hair loss, but it might actually be making it worse and contributing to your receding hairline. “Any sort of physical stress on the hair, such as rubbing and pulling, can lead to hair fall and breakage,” Dr. Ablon says. “Wearing a tight baseball cap is one such culprit. It causes rubbing on the front, sides and back of the head and hair, which in turn can lead to hair fall. If you use a shampoo and conditioner that moisturizes and strengthens the hair, it can help alleviate the amount of hair fall and breakage.”

Rough brushing and combing

It may not occur to you to be gentle whenever you pick up a comb, but aggressive brushing or combing puts a lot of physical stress on the hair fiber, and it can cause the cuticle to flake and strip away. “Aggressive brushing while your hair is wet is even worse—it can lead to excessive pulling and breakage,” Dr. Ablon says. Use grooming tools as intended and remember to go easy with them to prevent hair from breaking and a receding hairline.

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Diet

What you put into your body shows up in your hair. “Our diet is a huge part of it,” Dr. Ablon says. “You want to put the right ingredients and foods in your body, just as you want to use the right products with the right ingredients on your body for optimal hair health and minimal hair fall. People are generally eating healthier today, but we’re constantly on the go and on to the next thing, so we’re eating quickly, which means that we’re not retaining the proper nutrients from our food.” Supplements can be helpful in replacing these nutrients. Look for one designed specifically to nurture locks, such as Nutrafol ($88, nutrafol.com). Dr. Ablon recommends supplements that contain deep sea fish protein, biotin, and zinc to help stimulate hair growth.

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Over-Styling

We get that you want your hair to look good, but sometimes the tools you use to get you there aren’t doing you any favors. Using heat styling tools and over-styling play a role in contributing to hair loss, possibly even more than genetic predispositions. “We know that the more you do to your hair, the more you’re damaging the strands,” Dr. Ablon says. “Simplifying your hair regimen can help minimize damage and hair fall.”

Using the wrong grooming products

“The most important step any guy can take is choosing the right shampoo,” Dr. Ablon says. “Women’s shampoos and conditioners contain heavy moisturizers that would weigh down guys’ hair, leaving it lifeless and greasy looking. Men’s shampoos and conditioners, on the other hand, are made for men’s hair and under the assumption that men have shorter hair, which mean they more often have problems such as flaking.” Plus, remember that women’s hair products tend to smell more feminine.

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Products with harsh ingredients

“I don’t like to name names, but certain chemical ingredients found in hair products can cause hair loss,” says Dr. Ablon. “Preservatives that extend shelf life like formaldehyde are believed to affect hormones, and polyethylene glycol takes moisture away from hair shafts.” Avoid products with chemical ingredients like these as much as possible.